LAUSR

Background: Chiari type I malformation (CM-I) is characterized by the descent of the cerebellar tonsils ≥5 mm below the foramen magnum and is frequently associated with syringomyelia (SM). In professional athletes, these conditions may be incidentally discovered following mild trauma. However, the literature offers limited guidance on safe return-to-play criteria. Case Description: A 22-year-old professional rugby player was diagnosed with CM-I and SM. His only symptom was sleep apnea, confirmed by polysomnography. Magnetic resonance imaging (MRI) revealed a 17 mm tonsillar descent and a C3–C4 syrinx. Craniocervical decompression with duraplasty was performed. Five months postoperatively, the phase-contrast MRI (PC-MRI) demonstrated persistent SM with cerebrospinal fluid (CSF) flow velocities of 10 cm/s. By 16 postoperative months, the syrinx had resolved, and CSF velocities normalized. These findings guided the decision to clear the patient to return to professional contact sports. Conclusion: In this case, PC-MRI provided objective postoperative data that determined sufficient recovery from CM-I decompression and allowed the 22-year-old athlete to return to his high-impact sport.